1. Field of the Invention
This invention is directed to couplings for joining tubes, conduit and pipe that transport fluids, and more particularly to the tools to disconnect quick type couplings that lock with a circular spring.
2. Description of the Art
A class of quick couplings for tubes, conduit and pipe that permit a fluid-tight connection by hand in a short time are typical of those described in U.S. Pat. Nos. 3,711,125: 4,055,359, 4,401,326; 4,632,434; 5,094,494; and 5,529,348. The coupling of patent '359 by McWethy filed in 1975 is typical of this class of quick couplings and has been used in the transportation industry for connecting conduits and tubes of a fluid system carrying pressurized fluids such as air-conditioning fluid, gasoline, hydraulic fluids and the like. This coupling has been widely marketed as Ford's Spring-Lock.RTM. fitting. The coupling comprises a pair of fittings with one fitting end portion telescopically disposed within the end portion of the other outer fitting. An annular cage forming an annular chamber is externally mounted on one tube axially spaced from its end. The end of the outer tube is flared outwardly at its free end and extends into the cage through an annular cage aperture. A circular spring is interposed between the flared end and the inside of the cage to prevent axial movement of the tubes and fittings relative to one another when connected. A plurality of "O" rings are compressed between the telescoping ends to seal the connection and prevent leakage.
The patent of McWethy further discloses design criteria established for the coupling device to include "connections must be made by hand although use of a tool for disconnection is permissible". When taking the coupling apart, the circular spring is expanded over the flared end within the chamber of the cage to permit the withdrawal of the outer tube from the cage and subsequently disengagement of the tubes. In the patent of McWethy, the outward displacement of the circular spring is provided by a separate special tool. The tool simply displaces the circular spring in the radial outward direction but does not assist the user in pulling the tube fittings apart. Other tools used in the industry for radially displacing the circular springs are discussed later in this section.
The tubular coupling of patent '326 by Blair includes a snap ring to visually provide a positive indication that a coupling of the McWethy type has been properly connected. The spring lock coupling of patent '494 by McCornnell disclosed a modified cage portion and a double flared means on the end of the second tube fitting to assist in the quick coupling and positive sealing features of Mc Wethy. However, the radial displacement of the circular spring in the cage and pulling the tube fittings apart for disassembly is essentially the same as McWethy.
A quick disassembly is also important when removing vehicular components for maintenance, replacement and/or repair. An initial critical step in the disassembly of a spring-lock coupling is the radial displacement of the circular spring within the cage. The tool disclosed by McWethy is discussed above. Similar tools are available in the industry for this purpose. For example, an air conditioning and/or fuel line disconnect tool set, made by the Lisle Corporation of Clarinda, Iowa 51632 as model number 3700, is disclosed in U.S. Pat. No. 5,455,995. There are six tool sizes to cover the range of spring-lock couplings used by the industry. Other examples include the tool manufactured for AmPro tools Corporation of Los Angeles, Calif. 90015 as model number T70046 and the tool set manufactured for OEM Company Mineola, N.Y. as model number 25052.
The couplings of McWethy used in vehicle air conditioning systems have been marked with acute vehicle industry service problems. Generally speaking, when a connector has been in service for an extended length of time the "O" rings become dry and rigid and the fitting parts become corroded due to the nature of the air conditioning fluid at the interface between fittings. To help solve these problems U.S. Pat. No. 4,728,130; U.S. Pat. No. Re. 33,946; and U.S. Pat. No. 5,480,193 disclose a split clamp to fit snugly over the cage of the coupling to secure the cage and prevent loss of fluid from the fittings. The clamps, however, add rigidity to the connection and do not permit movement between connected parts that are desirable for absorbing vehicular vibrations. The clamps must also be removed before the tubes can be disconnected.
The industry continues to use the same general construction of the McWethy coupling which inherently demands a relatively high level of manual forces to achieve a quick connection and particularly to achieve a quick disassembly. This is the result of the dry O-rings and corrosion which results is an initial locking effect that requires a high axial load to break the fittings apart so they can be displaced axially with respect to one another. The combination tool disclosed by Scarborough in U.S. Pat. No. 5,671,520 not only radially displaces the circular spring in the cage but also forces the fittings to be axially displaced with respect to one another to break the coupling apart. The tool has three long handles to provide a mechanical advantage in breaking the locking effect. This advantage is somewhat limited with the tool of Scarborough. A problem continues to exist in operating three handles with two hands and tightly locked joints are difficult to beak loose
Accordingly, an object of the present invention is to provide a hand held tool to disconnect a tubular conduit having quick-connect type fittings with a circular spring by both displacing the spring and breaking apart the fittings.
Another object of the present invention is to provide a low cost disconnect tool having interchangeable parts that allow the tool to be adapted to the different sizes of tubular conduits or pipes.
Yet another object of the present invention is to provide a hand held tool that can disconnect quick-connect type fittings of tubular conduit or pipe with relatively little effort in a relatively short period of time.
Still another object of the present invention is provide an assembly for connecting and disconnecting a tubular conduit or pipe using quick-connect fittings with a circular spring for connecting together the two ends of the conduit or pipe and a disconnect tool for taking the fittings apart.